Regularly tangled compact yarn process

ABSTRACT

A process for interlacing synthetic continuous multifilament yarn comprising pulsing of the threadline while under tension with at least one stream of pressurized fluid emitting through a Coanda-effect fluidic oscillator.

United States Patent Barlow et al.

[ *Jan. 25, 1972 REGULARLY TANGLED COMPACT YARN PROCESS lnventors: Paul D. Barlow; John L. Marshall, Jr.,

both of Pensacola, Fla.

Assignee: Monsanto Company, St. Louis, Mo.

Notice: The portion of the term of this patent subsequent to Jan. 21, 1986, has been disclaimed.

Filed: June 23, 1969 Appl. No.: 835,595

Related US. Application Data Continuation-impart of Ser. No. 720,798, Apr. 12, 1968, Pat. No. 3,478,398, which is a division of Ser. No. 670,137, Sept. 25, 1967, Pat. No. 3,422,516.

us. c1 ..2s/72.12, 137/815 1111. C1 ..D02g l/l6 Field ofSearch ..2s/72.12, 1.4; 137/81.5

References Cited UNITED STATES PATENTS 1/1962 Breen ..28/72.12 X 12/1969 Jackson ..28/72.l2 UX 11/1963 Bunting et al. ..28/1 .4 X 1/1964 Breen et al.... .28/72.l2 X

4/1966 Bauer ..137/81 5 8/1966 Wadey 137/81 5 H1969 Barlow et al.. 28/7212 2/1969 Cerutti et al..... .....28/l.4 6/1969 Buzano ..28/l.4 X 12/1969 Cerutti et al ..28/l.4

Primary ExaminerRobert R. Mackey At!0rneyl(el1y O. Corley and Stanley M. Tarter ABSTRACT A process for interlacing synthetic continuous multifilament yarn comprising pulsing of the threadline while under tension with at least one stream of pressurized fluid emitting through a Coanda-effect fluidic oscillator.

3 Claims, 5 Drawing Figures PATENTEDJANZSISYZ 3.'s3s;e01

PAU BARLOW JOHN L. RSHALL, JR. 9/64 0. a

ATTORN INVENTORS REGULARLY TANGLED COMPACT YARN PROCESS CROSS-REFERENCES TO RELATED APPLICATIONS The present application is a continuation-in-part application of copending application Ser. No. 720,798, filed Apr. 12, 1968, now US. Pat. No. 3,478,398, which in turn is a divisional application of Ser. No. 670,137, filed Sept. 25, 1967, now US. Pat. No. 3,422,516.

BACKGROUND OF THE INVENTION Yarn jet apparatus of various types utilizing high-velocity fluids have been used in the treatment of textile yarns as the same moves axially therethrough. Air jets have been used for transporting yarn from one point to another. It is also known to use jets for opening filamentary bundles by disrupting the parallelism of the filaments.

In recent times jets have been used to texture yarn thereby to render the same more voluminous. One operation for doing this, as disclosed in US. Pat. No. 2,783,609, involves passing the yarn under reduced tension through a confined zone provided by a jet in which a fluid, such as air, is introduced under pressure to cause a turbulence such that loops or convolutions are formed in the yarn. Using a slight variation from this justdescribed operation, one is able to produce a random, threedimensional crimp in thermoplastic filaments, thereby texturing the same by employing a plasticizing fluid instead of air. Ordinarily steam at a temperature sufficiently high to efiect plasticization of the filaments is fed to the jet through which the filamentary material moves.

Another known treatment of filamentary yarn in a fluid jet obviates the need of imparting low twist therein needed for maintaining the continuity of the threadline in various handling operations, by causing the individual filaments to become interlaced. Such a yarn interlacing operation is disclosed in US. Pat. No. 2,985,995, and involves passing yarn through a jet under controlled tension. In the jet the filaments are whipped back and forth and become interlaced to form a structure which could be referred to as a false braid. Even though the yarn may have no twist, it performs in certain textile operations as though twist of several turns per inch were present. Although the interlacing is random, such operation has the drawback that optical defects appear in fabric woven from the interlaced yarn. Irregular light reflections or transmissions result because large and small groups of the filaments become so erratically entangled that the thread bundle no longer is round along its length, but rather has areas that are ribbonlike. The yarn thus has an apparent variable denier, in some cases. This irregular phenomenon is often referred to in the trade as flashes and is quite undesirable from an aesthetic standpoint.

In a slight variation from the interlacing procedure just described, synthetic manmade filaments which have been drawn can be relaxed to reduce the shrinkage thereof at the same time interlacing is accomplished. Instead of air, steam is often used as the interlacing fluid and induces the relaxation of the yarn. The undesirable flashes also occur in a woven fabric made from relaxed and interlaced yarn when known jet apparatus are used.

It has been found in accordance with the present invention that yarn can be efficaciously treated in a novel yarn jet such that one can produce interlaced yarn exhibiting substantially no flashes. The same apparatus can be used for producing relaxed, interlaced yarn, as well as textured yarn having loops or random three-dimensional crimps or both of these latter characteristics.

SUMMARY OF THE INVENTION It has been found that compact interlaced synthetic continuous multifilament yarn of low or zero twist but having handling properties of much greater twist and being substantially free of flashes can be produced. Along its length the yarn is provided with regularly periodically occurring portions of individual filament compact interlacements separated by regularly periodically occurring portions of individual filament compact substantial parallelism wherein the filaments are only slightly interlaced. The frequency of occurrence of filamentary compact or tight interlacements is about 0.1 to 5 per inch length of yarn. The lengths of the entangled compact portions can be made to approximate the lengths of the unentangled compact portions, if desired.

Apparatus for extremely rapid intermittent treatment of yarn in a jet of special construction is provided. At a frequency of about 25 cycles per second (c.p.s.) up to 10,000 cycles per second, fluid pulses are applied to traveling yarn at closely spaced intervals in a jet apparatus having a zone for yarn passage therethrough. A Coanda-effect fluidic diverting valve is provided to have at least one output port opening into the zone for intermittent fluid contact with the yarn. Means are associated with the valve for rapidly alternating or oscillating substantially the complete flow of the fluid from one output port to the other output port to intermittently deliver treating fluid to the yarn as the same moves through the zone. When both output streams impinge on the yarn, the fluid paths preferably form an angle from their engagement with the yarn of from at least 10 to 180. Depending upon the selected tension on the yarn in the jet, the yarn can be interlaced or rendered bulky. When a heated fluid is used, relaxation of the yarn can be simultaneously accomplished.

In accordance with the process of the invention, synthetic thermoplastic multifilament yarn is treated as it moves through fluid pulses. In one embodiment, substantially complete flow of the fluid is oscillated between two discharge intersecting points at a frequency of about 50 to 10,000 cycles per second (c.p.s.) so that as the yarn moves through a confined zone the yam is regularly and intermittently treated with the fluid at such frequency. When a textured yarn is produced, one should preferably employ a yarn overfeed to the zone of 10 to 50 percent and steam as the fluid at a temperature of at least 350 F. but below the temperature where filament sticking occurs. When freshly drawn nylon yarn is treated, such yarn will normally be delivered to the confined zone at an overfeed of 4-15 percent. Using an overfeed of 4-15 percent with steam of at least C. will result in the formation of relaxed yarn with individually interlaced filaments.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a Coanda-effect jet device useful in the practice of the present invention.

FIG. 2 shows the device in central cross section taken along line 2-2 of FIG. 1 and illustrates the fluid flow from the source thereof to one output port.

FIG. 3 shows schematically an apparatus assembly including the jet together with two sets of rolls for controllably delivering the yarn to and from the jet.

FIG. 4 shown schematically an apparatus assembly for drawing synthetic filaments and immediately thereafter treating the same in the jet to relax and interlace simultaneously the filaments.

FIG. 5 shows an alternative embodiment of the invention wherein only one fluid outlet passage is connected to the yarn passage.

THE DISCLOSURE OF THE INVENTION With reference first to FIG. 1, yarn 10 undergoing treatment passes through a tubular member'l I of the jet apparatus generally denoted by numeral 12. Conduit 13 connects the apparatus to a source of high-velocity fluid, not shown, that is discharged into a Coanda-effect fluid diverting valve 14. The valve contains a network of internal confined passages for the fluid movement therethrough. The valve has no moving parts; and the control of the high-energy stream of fluid supplied from conduit 13 as to its intermittent flow through passages 15 and 16 is made by a low-energy stream of fluid oscillating in conduit 17. Valve 14 has two discharge intersecting output ports 18 and 19 opening into tube 11 for fluid contact with the yam. A solid tapered splitter block 20 splits the fluid delivered from the input port 21 to the output ports. Conduit 17 forms a closed fluid feedback circuit having opposed control ports 22 and 23 at the downstream edges of port 21, as seen in FIG. 2. These control ports communicate with the flow of fluid between the input port and the tapered block so that oscillating shockwaves move in conduit 17 to cause substantially complete flow of fluid to be moved regularly and intermittently from one output port to the other output port.

The abrupt and virtually complete change of fluid flow back and forth from passages 15 and 16 can better be seen by reference to FIG. 2. For most complete switching of the air flow, passages 15 and 16 as well as port 21 are rectangular in cross section, and the upstream edge of splitter block 20 is located downstream from port 21 about six or more times the width of port 21. The walls of passages are flat and provide more secure attachment of the fluid to the outer sides of the passages so that more complete flow of the fluid alternately therethrough is attained. In an exemplary embodiment, passages 15 and 16 were 0.078X0.078 inch square, while port 21 was 0.078 inch deep and 0.047 inch wide just upstream of control ports 22 and 23. Typical air consumption is between and 100 standard cubic feet of air per hour, corresponding to fluid velocities of about 70 to 700 feet per second. Somewhat higher velocities can be used if desired.

In valve 14, the instant the jet of fluid switches to the upper passage and discharges perpendicularly with respect to the yarn movement, fluid begins to flow through port 23 and then through conduit 17 providing a generally circular feedback path. This fluid flow is preceded by propagation of a shock wave. When this shock wave front collides with the main jet of fluid, sufficient energy is transferred to cause the main jet to be diverted to the bottom passage 16. The identical action then occurs when the succeeding shock wave travels in the reverse direction through conduit 17. As can be seen, the frequency of oscillation of the jet is a function of the length of feedback path provided by conduit 17. As indicated previously, switching of fluid using this kind of jet has been attained at frequencies over 10,000 c.p.s. A frequency of above 50 c.p.s. is preferred. 7

It will be noted that both streams of fluid impinge on the threadline perpendicularly in the same plane. However, the paths of the fluid discharged from passages and 16 intersect at an angle. Although this angle as formed by the intersection of the extended axes of passages 15 and 16 is not critical, better control on the filament action within the jet is attained when the angle is at least 10 with even better stability being accomplished at or near 180. If desired, passage 16 can discharge to the atmosphere, so that only the fluid from passage 15 enters tube 1 1, as shown in FIG. 5.

In FIG. 3, yarn 10 is fed to the jet apparatus 12 by a pair of feed rolls 24. A second pair of rolls 25 withdraws the yarn from the jet at a controlled speed. Where a textured yarn is to be produced by the use of the apparatus, an over-feed of the yarn to the jet of about 10 percent or more up to about 50 percent is required, thus the filaments in the jet are at all times slack. Where crimps in the yarn provide the texturing, a heated turbulent fluid is supplied to the jet and the yarn should be made of thermoplastic polymer. When loopy yarn is desired to be produced, the yarn should be withdrawn from the jet at an abrupt angle so that the fluid discharge through the bottom of tube 11 acts on the slack filaments to flip loops therein.

Particularly when an interlaced yarn is desired to be produced, the yarn should be maintained under positive tension as it moves through the jet. The tension should be sufficient to prevent looping or crimping of the filaments, and usually will be between 0.01 and 0.95 grams per denier (g.p.d.). Preferably the tension is between about 0.05 and 0.25 grams per denier when producing a compact yarn. The yarn linear speed and the pulse repetition rate are selected so that each 100 inches of yarn receives between about 10 and 500 fluid pulses.

In FIG. 4, apparatus is shown adapted for processing undrawn synthetic thermoplastic multifilarnent yarn to produce a drawn, relaxed and interlaced yarn. Feed package 26 provides a source of undrawn yarn which is withdrawn therefrom by feed rolls 27 for delivery to the drawing zone 28 at a metered rate. Snubbing pin 30 can be employed to localize the point of draw of the filament bundle. Draw roll 31 operates at a surface speed considerably greater than the delivery speed of yarn to the zone 28 to provide the desired amount of draw or molecular orientation resulting from such drawing. Draw roll 31 has a step to provide controlled relaxation of the filaments. From the draw zone the yarn passes a plurality of times around separator roll 32 and the portion of roll 31 having the larger diameter to provide sufficient drawing force without appreciable yarn slippage therearound. Next the yarn is moved around roll 33; and on its way to the portion of roller 31 having the smaller diameter the yarn is treated in jet 12. The amount of stepdown will be dependent upon whether a bulky or interlaced compact yarn is to be provided. Where a crimpy or loopy yarn is desired, the stepdown will be large enough to provide the slack needed for texturing. When an interlaced yarn is desired, the amount of stepdown, if any, will be less and is controlled so that the yarn never becomes slack. If heated fluid is used, the yarn may undergo shrinkage and a stepdown roll will be needed even though an interlaced untextured yarn is desired since the creeping back of the yarn due to shrinkage will compensate for up to about l2 percent or more of overfeed and will give rise to the presence of sufficient tension for making an interlaced yarn. Normally nylon yarn will retract 4-15 percent during interlacing accomplished immediately after drawing with steam having a temperature of at least 350 F. Upon its return to the lower step of roll 31, the yarn is taken up in an orderly manner. As illustrated in FIG. 4, a ringtraveller takeup device 34 is used for this purpose which ordinarily places a twist in the threadline. When the yarn has been interlaced, it need not be packaged with a twist, since an interlaced yarn already has the handling characteristics of a twisted yarn.

The invention is generally applicable to all manmade yarns. It is particularly useful in treating synthetic multifilament yarn made from linear polyamides, commonly referred to as nylons, including nylon66, nylon-6, nylon-7, nylon 6-10, nylon 11, nylon 6/66, nylon 61661610, etc. Additional suitable yarns can be made from linear polyesters including polyethylene terephthalate; vinyl polymers including polyvinyl chloride, polyvinylidene chloride and copolymers thereof; acrylonitrile polymers, polyhydrocarbons including polyethylene and polypropylene, etc.

The following examples illustrate specific embodiments of the invention, when using the FIG. 1 jet device.

EXAMPLE I Polyhexamethylene adipamide yarn composed of 34 filaments and a drawn denier of 70 passed through jet 12 using yarn feeding and withdrawing wheels synchronized to maintain 0.20 gram per denier tension on the filaments. The yarn speed is 300 yards a minute. Air at ambient temperature moving at A sonic velocity enters the jet to treat the yarn moving in tube 11 of the jet. The thus-treated yarn is packaged without twist. It has handling properties comparable to twisted yarn of a few turns per inch. The jet has a conduit 17 designed to provide 60 c.p.s. oscillation of the air from one outlet to another. The interlacing of the filaments follows a systematic pattern but is so finely dispersed along the threadline that no optical defects appear in fabric woven therefrom.

The number of entangled compact portions and the number of unentangled compact portions are about one each per 3 inches of yarn length.

When conduit 17 is removed or plugged to prevent the oscillation of the air flow, there is interlacing of the filaments; but the yarn does not have a uniformly'round cross section along its length. Optical defects appear in fabric woven therefrom.

The same observation of no optical defects is made with polyethylene terephthalate 70 denier, 34 filament yarn, when likewise treated in the jet as described in this example.

EXAMPLE ll Drawn polyhexamethylene adipamide yarn of 70 denier, 34 filament count is passed through jet 12 at 200 yards per minute with overfeed of 25 percent. Steam at 200 C. is introduced to jet l2 and impinged on the yarn at a frequency of 75 c.p.s. The resulting yarn has a bulky appearance with the individual filaments thereof showing a random three-dimensional crimp.

EXAMPLE III Drawn polyhexamethylene adipamide yarn of 70 denier, 34 filament count is passed through jet 12 with a percent overfeed. The yarn speed is 200 yards a minute. Air ambient temperature at a sonic velocity is the treating fluid which is switched at 60 c.p.s. As the yarn leaves the jet, it is directed at right angles therefrom. The resulting yarns have a multitude of loops along their length.

EXAMPLE lV Polyhexamethylene adipamide yarn of 13 filaments is drawn to a final denier of 40 using the apparatus of FIG. 4. The yarn moves around the draw roll 31 at a speed of 395 yards per minute, to the jet 12 and around the lower step of roll 31 providing a yarn overfeed of 12 percent to the jet. Superheated steam at l50 C. moves through jet l2 and impinges on the yarn at a frequency of 75 c.p.s. The resulting yarn is relaxed and interlaced. No flashes are observed in the interlaced yarn.

The number of entangled compact portions and the number of unentangled compact portions are about one each per 3 inches of yarn length.

Numerous advantages are provided by the present invention. A novel and useful jet for treating filaments is disclosed. The treating fluid is intermittently applied to the filaments at extremely high frequencies with the result that any nonuniformities inherent in the treating processes are so fine and well dispersed that they are not apparent. At low frequencies novel effects can be obtained in the treated yarn. The jet apparatus has no moving parts and can be made of practically any material that can be cast, molded, machined or otherwise shaped. The diverting valve switches the fluid flow quickly and almost completely with little or no vibration. Furthermore, the jet requires very little maintenance. The jet can be used for a variety of purposes including bulking yarn, interlacing yarn, relaxing yarn, interlacing and relaxing yarn, simultaneously. Since the pulse repetition rate is substantially independent of applied pressure, the interlacing intensity can be selected independently of frequency. This affords great flexibility in adjusting the mechanism for any desired process or product. Other textile uses are readily apparent.

What is claimed is:

l. A process for producing an interlaced threadline, comprising:

a. passing pressurized fluid through a Coanda-effect fluidic oscillator having first and second alternately pulsed output streams, and

b. applying at least one of said streams to a running threadline composed of a plurality of continuous parallel filaments whereby said threadline is subjected to pulses of said fluid at regularly spaced intervals along its length, said threadline being under a tension of between 0.01 and 0.95 grams per denier.

2. The process defined in claim 1, wherein said tension is between 0.05 and 0.25 grams per denier.

3. The process defined in claim 1, wherein the repetition rate of said pulses and the linear speed of said threadline are such that each inches of said threadline receives between 10 and 500 of said pulses. 

1. A process for producing an interlaced threadline, comprising: a. passing pressurized fluid through a Coanda-effect fluidic oscillator having first and second alternately pulsed output streams, and b. applying at least one of said streams to a running threadline composed of a plurality of continuous parallel filaments whereby said threadline is subjected to pulses of said fluid at regularly spaced intervals along its length, said threadline being under a tension of between 0.01 and 0.95 grams per denier.
 2. The process defined in claim 1, wherein said tension is between 0.05 and 0.25 grams per denier.
 3. The process defined in claim 1, wherein the repetition rate of said pulses and the linear speed of said threadline are such that each 100 inches of said threadline receives between 10 and 500 of said pulses. 